Aliphatic polyesters containing sulphur, and their use as stabilizers for polymers

Abstract

Aliphatic polyesters containing sulphur, which contain the sulphur as structural units in the form of sulphide or disulphide groups in both the acid component and the diol component, a process for the preparation of these polyesters, and also polymers containing these polyesters.

We claim: 
     
       1. Sulphur-containing, aliphatic polyesters which have been built up from dicarboxylic acids (esters) of the formula (I) and diols of the formula (II) ##STR5## wherein R, R 1 , R 2  and R 3  independently of one another denote hydrogen or an alkyl radical having 1 to 4 carbon atoms, a denotes 1, 2 or 3,   b and d denote 0, 1 or 2 or 3 and   e and f denote 1, 2 or 3, and which have a molecular weight of 500 to 7,000.     
     
     
       2. Sulphur-containing, aliphatic polyesters according to claim 1, in which the diol is one of the compounds ##STR6## or a mixture of these compounds. 
     
     
       3. Sulphur-containing, aliphatic polyesters according to claim 1, in which the dicarboxylic acid (ester) is one of the compounds ##STR7## or mixtures thereof wherein R and R 1  denote hydrogen or alkyl groups having 1 to 4 carbon atoms. 
     
     
       4. Process for the preparation of sulphur-containing, aliphatic polyesters according to claim 1, characterized in that dicarboxylic acids (esters) (I) and a diol (II) are mixed and are subjected to polycondensation at 50°-250° C., if appropriate in the presence of a catalyst, until a molecular weight of 500 to 7000 has been reached. 
     
     
       5. Process according to claim 4, characterized in that diols of the formulae ##STR8## or mixtures thereof and a dicarboxylic acid (ester) of the formulae ##STR9## wherein R and R' denote hydrogen or C 1  -C 4  -alkyl, or mixtures thereof, are employed. 
     
     
       6. Synthetic polymers, in particular thermoplastic moulding compositions, characterized in that they contain 0.1 to 5% by weight of a polyester according to claim 1.